public function initialize_cart() {
		// Cart needs customer info.
		if ( is_null( $this->customer ) || ! $this->customer instanceof WC_Customer ) {
			$this->customer = new WC_Customer( get_current_user_id(), true );
			// Customer should be saved during shutdown.
			add_action( 'shutdown', array( $this->customer, 'save' ), 10 );
		}
		if ( is_null( $this->cart ) || ! $this->cart instanceof WC_Cart ) {
			$this->cart = new WC_Cart();
		}
	}